The human spine is made up of a column of thirty-three bones and their adjoining structures. The bodies of these vertebrae are connected by anterior and posterior ligaments and by discs of fibrocartilage generally known as intervertebral discs. These discs are positioned between opposite faces of adjacent vertebral bodies. This column of vertebrae and intervertebral discs form a central axis that supports the head and torso. These vertebrae also enclose an opening through which the spinal cord passes.
The presaccral vertebrae are normally held in position to one another by the intervertebral discs, ligaments and musculature of the body. These vertebrae move relative to adjacent vertebrae thus permitting the head to be turned relative the body and providing a wide range of flexibility to the spine.
One of the most costly health problems in society involves back pain and pathology of the spine. These problems can affect individuals of all ages and can result in great suffering to victims. Back pain can be caused by several factors such as congenital deformities, traumatic injuries, degenerative changes to the spine, and the like. Such changes can cause painful excessive motion, or collapse of a motion segment resulting in the contraction of the spinal canal and compression of the neural structures, causing debilitating pain, paralysis or both, which in turn can result in nerve root compression or spinal stenosis.
Nerve conduction disorders can also be associated with intervertebral discs or the vertebrae themselves. One such condition is herniation of the intervertebral disc, in which a small amount of tissue protrudes from the sides of the disc into the foramen to compress the spinal cord. A second common condition involves the development of small bone spurs, termed osteophytes, along the posterior surface of the vertebral body, again impinging on the spinal cord.
Upon identification of these abnormalities, surgery may be required to correct the problem. For those problems associated with the formation of osteophytes or herniations of the intervertebral disc, one such surgical procedure is intervertebral discectomy. In this procedure, the involved vertebrae are exposed and the intervertebral disc is removed, thus removing the offending tissue or providing access for the removal of the bone osteophytes. A second procedure, termed a spinal fusion, may then be required to fix the vertebrae together to prevent movement and maintain a space originally occupied by the intervertebral disc. Although this procedure may result in some minor loss and flexibility in the spine, due to the relatively large number of vertebrae, the minor loss of mobility is typically acceptable.
During an intervertebral discectomy, a prosthetic implant or spinal implant is inserted in the vertebral disc space. This prosthetic implant is often a bone graft removed from another portion of the patient""s body, termed an autograft. The use of bone taken from a patient""s body has the important advantage of avoiding rejection of the implant, but has several shortcomings. There is also a risk of opening a second surgical site to obtain the implant, which can lead to infection or pain for the patient, and the second surgical site is weakened by the removal of material. The bone implant may also not be perfectly shaped for placement between the vertebrae, thus leading to slippage or absorption of the implant, or failure of the implant to fuse with the vertebrae.
Other options for a graft source of implant are bone removal removed from cadavers, termed allograft, or from other species, termed a xenograft. In these cases, while there is the benefit of not having a second surgical site, thus reducing the incidence of infection or pain at such second site, there is increased difficulty associated with graft rejection and the risk of transmitting communicable diseases.
An alternative approach to using a bone graft is using a manufactured implant made of synthetic material which is biologically compatible with the body and the vertebrae. Several compositions and geometries of such implants have been utilized, ranging from simple blocks of material to carefully shaped implants, with varying success.
There has been an extensive number of attempts to develop an acceptable prosthetic implant that can be used to replace an intervertebral disc and yet maintain the stability of the intervertebral disc space between adjacent vertebrae, at least until complete arthrodesis is achieved. For fusion to occur between the prosthetic implants, it is typically necessary to prepare the vertebrae to be fused by breaking through or cutting into the hardened outside plates of the bone to allow the interposed bone graft to come into direct contact with the prosthetic implant, thereby tricking the body into attempting to heal itself and to bond with the prosthetic implant. While many types of synthetic prosthetic devices have been proposed, the success rates have been low and the surgical procedures have been complicated and often traumatic to the patient.
One of the more prevailing designs of these prosthetic implants takes the form of a cylindrical implant. These types of prosthetic implants are represented by Brantigan U.S. Pat. No. 4,878,915 and Ray U.S. Pat. No. 4,961,740, which are incorporated herein by reference. In these cylindrical implants, the exterior portion of the cylinder can be threaded to facilitate insertion of the prosthetic device. Some of these prosthetic implants are designed to be pounded into the intervertebral disc space. These types of devices are represented in Brantigan U.S. Pat. No. 4,834,757 and Brantigan U.S. Pat. No. 5,192,327, which are incorporated herein by reference. The Brantigan and Ray patents disclose prosthetic implants wherein the transverse cross-section of the implant is constant throughout the length of the implant, and is typically in the formed of a circular cylinder.
Other prosthetic implants have been developed that do not have a constant cross-section. For instance, the patent to McKinna U.S. Pat. No. 4,714,469 illustrates a spherical implant with elongated protuberances that project into the vertebral end plate. The implant of Bagby U.S. Pat. No. 4,934,848 is in the form of a sphere which is positioned between the centrums of the adjacent vertebrae. Both of these disclosures are incorporated herein by reference.
Various prosthetic implants can be generally divided into two basic categories, namely solid implants and implants designed to encourage bone growth. Solid implants are represented by U.S. Pat. Nos. 4,878,915 and 4,349,921, which are incorporated herein by reference. The other patents discussed above permit bone to grow across and/or into the implant. It has been found that devices which promote natural bone growth achieve a more rapid and stable arthrodesis. These implants are typically filled with autologous bone prior to insertion into the intervertebral disc space. These implants typically include apertures which communicate with openings in the implant, thereby providing a path for tissue growth between the vertebral end plate and the bone or bone substitute within the implant.
A number of difficulties remain with the use of these prior art prosthetic implants. While it is recognized that hollow implants which promote bone growth into the implant is an optimal technique for achieving fusion, most of these devices have difficulty achieving this fusion, at least without the aid of some additional stabilizing device, such as a rod or plate. Moreover, some of these devices are not structurally strong enough to support the heavy loads applied to the most frequently fused vertebral levels, namely those in the lower lumbar spine.
Many of these problems with past prosthetic implants have been overcome by the prosthetic implants disclosed in U.S. patent application Ser. No. 09/865,114 filed May 24, 2001 entitled xe2x80x9cSpherical Spinal Implantxe2x80x9d and U.S. patent application Ser. No. 09/494,645 filed Jan. 31, 2000 entitled xe2x80x9cSpinal Fusion Implantxe2x80x9d, now U.S. Pat. No. 6,245,108, both of which are incorporated herein by reference. These two patent applications disclose an improved prosthetic implant in the form of a sphere or cage, which implants can permit bone growth with or without the aid of additional devices, and which prosthetic implants are structurally strong to support the heavy loads applied to such implants.
Although many of the past problems with prosthetic devices have been overcome as stated above, there remains a need for a device which facilitates in easily and properly inserting one or more prosthetic implants into the intervertebral disc space while minimizing damage to the spinal cord and/or surrounding tissue. In view of the present state of technology related to prosthetic implants, there is a continued need for new devices and methods to properly and successfully insert prosthetic implants into the intervertebral disc space.
The present invention relates to prosthetic implants to be placed into the intervertebral disc space, and more particularly, to an apparatus and method for facilitating in the guiding and/or inserting of one or more prosthetic implants into the intervertebral disc space.
In accordance with the principal feature of the present invention, there is provided an insertion tool which can be used with one or more prosthetic implants, which tool is at least partially designed to guide and/or position one or more prosthetic implants into at least a portion of the intervertebral disc space between two adjacent vertebrae. The insertion tool is designed to facilitate the surgical procedure of inserting and/or positioning one or more prosthetic implants between two or more vertebrae, thereby simplifying the surgical procedure. The insertion tool also and/or alternatively facilitates in minimizing or preventing damage to the spinal cord and/or other vital tissue (e.g. large blood vessels, neural structures, muscle, etc.) about the vertebral disk space, thereby minimizing injury and/or complication to the patient during a surgical procedure when inserting one or more prosthetic implants between two or more vertebrae.
In accordance with one aspect of the present invention, there is provided an insertion tool that includes a posterior end portion or top portion which has a shape and/or size that approximates the anterior curve of the intervertebral disc space. In one embodiment of the invention, the posterior end portion of the insertion tool is sized and/or shaped such that at least a majority of the posterior end portion lies within the vertebral annulus (i.e. the ridge at the top/bottom of the vertebrae that matches the border of the spinal discs) when the insertion tool is inserted into the intervertebral disc space. In one aspect of this embodiment, the prosthetic end portion is shaped and/or sized such that at least about 60% of the posterior end portion lies within the annulus when the insertion tool is inserted into the intervertebral disc space. In another and/or alternative aspect of this embodiment, the prosthetic end portion is shaped and/or sized such that at least about 70% of the posterior end portion lies within the annulus when the insertion tool is inserted into the intervertebral disc space. In still another and/or alternative aspect of this embodiment, the prosthetic end portion is shaped and/or sized such that at least about 80% of the posterior end portion lies within the annulus when the insertion tool is inserted into the intervertebral disc space. In yet another and/or alternative aspect of this embodiment, the prosthetic end portion is shaped and/or sized such that at least about 90% of the posterior end portion lies within the annulus when the insertion tool is inserted into the intervertebral disc space. In still yet another and/or alternative aspect of this embodiment, the prosthetic end portion is shaped and/or sized such that substantially all of the posterior end portion lies within the annulus when the insertion tool is inserted into the intervertebral disc space. In another and/or alternative embodiment of the present invention, the posterior end portion is formed of one or more annular or arcuate portions. In one aspect of this embodiment, the posterior end portion is formed by a single arcuate portion of the spinal insert. In one particular configuration of this aspect, the radius of curvature of the arcuate portion is substantially constant throughout the length of the arcuate portion. In another and/or alternative configuration of this aspect, the radius of curvature of the arcuate portion varies at least once along the length of the arcuate portion. In another and/or alternative aspect of this embodiment, the posterior end portion is formed by a plurality of arcuate sections and at least one non-arcuate section. In one particular configuration of this aspect, all the arcuate sections have substantially the same radius of curvature. In another and/or alternative configuration of this aspect, one or more of the arcuate sections have a different radius of curvature from at least one other arcuate section. In still another and/or alternative specific configuration of this aspect, the one or more non-arcuate sections are substantially linear.
In still another and/or alternative aspect of the present invention, the posterior end portion has a total angle of curvature for a particular insertion device which is selected so that the insertion tool can position and/or maintain one or more prosthetic implants in a desired location within the intervertebral disc space. In one embodiment of the invention, the cumulative or total angle of curvature of the posterior end portion is at least about 45xc2x0. In one aspect of this embodiment, the total angle of curvature of the posterior end portion is at least about 60xc2x0. In another and/or alternative aspect of this embodiment, the total angle of curvature of the posterior end portion is at least about 90xc2x0. In still another and/or alternative aspect of this embodiment, the total angle of curvature of the posterior end portion is at least about 120xc2x0. In yet another and/or alternative aspect of this embodiment, the total angle of curvature of the posterior end portion is at least about 150xc2x0. In still yet another and/or alternative aspect of this embodiment, the total angle of curvature of the posterior end portion is at least about 180xc2x0. In yet a further and/or alternative aspect of this embodiment, the total angle of curvature of the posterior end portion is at least about 190xc2x0. In still yet a further and/or alternative aspect of this embodiment, the total angle of curvature of the posterior end portion is at least about 200xc2x0. In still another and/or alternative aspect of this embodiment, the total angle of curvature of the posterior end portion is at least about 210xc2x0. In still yet another and/or alternative aspect of this embodiment, the total angle of curvature of the posterior end portion is at least about 220xc2x0.
In yet another and/or alternative aspect of the present invention, the cross-sectional shape and/or size (i.e. thickness) for the posterior end portion of the insertion tool is selected to facilitate in the ease of positioning and/or maintaining one or more prosthetic implants within the intervertebral disc space, to facilitate in the insertion and/or removal of the insertion tool from the intervertebral disc space, to maintain the proper spacing of the intervertebral disc space during the insertion and/or positioning of one or more prosthetic implants within the intervertebral disc space, and/or to minimize damage to surrounding tissue during the insertion and/or positioning of one or more prosthetic implants within the intervertebral disc space. In one embodiment of the invention, the cross-sectional shape and/or size of the prosthetic end portion is substantially constant along the length of the posterior end portion. In another and/or alternative embodiment of the invention, at least a section of the cross-sectional shape and/or size of the posterior end portion is different from another section of the posterior end portion. In still another and/or alternative embodiment of the invention, at least a section of the prosthetic end portion has a substantially circular, square, or rectangular cross-sectional shape. As can be appreciated, other cross-sectional shapes can be used, such as ovoid, polygonal, D-shaped, etc. In yet another and/or alternative embodiment of the invention, the maximum size (i.e. cross-sectional length or diameter) of the prosthetic end portion is less than the minimum space between two adjacent vertebrae that form the intervertebral disc space. Such a thickness of the prosthetic end portion facilitates in the ease of inserting and/or removing the insertion tool from the intervertebral disc space during a surgical procedure. In still yet another and/or alternative embodiment of the invention, at least a section of the posterior end portion has a maximum size which is greater than or equal to the minimum space between two adjacently positioned vertebrae which form the intervertebral disc space. An insertion tool having this design facilitates in at least partially maintaining the spacing between the two adjacent vertebrae so as to facilitate in positioning one or more prosthetic implants into the intervertebral disc space during a surgical procedure. In one aspect of this embodiment, at least a portion of the posterior end portion is expandable and/or contractable, thereby allowing the maximum size of the posterior end portion to be variable. In one non-limiting example, the maximum size of the posterior end portion can be selected to be less than or equal to the minimum space between two adjacent vertebrae to facilitate in the ease of insertion of the insertion tool between two vertebrae. Thereafter, the maximum size can be caused to increase to force apart the two adjacent vertebrae so as to facilitate in the insertion of the implant between the two adjacent vertebrae. After the one or more implants have been properly positioned and/or inserted between the two adjacent vertebrae, the maximum size of the posterior end portion is reduced so that it is less than or equal to the minimum space between the two adjacent vertebrae to facilitate in the removal of the insertion tool from the surgical site. As can be appreciated, the increasing and/or decreasing in the maximum size of one or more portions of the posterior end of the insertion tool can be used in many other manners to facilitate in the positioning and/or insertion of one or more implants between two adjacent vertebrae, and/or to facilitate in the insertion and/or removal of the insertion tool at the surgical site.
In still yet another and/or alternative aspect of the present invention, the insertion tool includes a body portion which is connected to at least one end of the posterior end portion. The body portion is designed to have a sufficient length to allow the surgeon to properly extend the posterior end portion into the intervertebral disc space and/or to maneuver the posterior end portion in the intervertebral disc space during a surgical procedure. In one embodiment of the invention, the body portion is made of a material which is similar to that of the posterior end portion. In another and/or alternative aspect of this embodiment, the body portion is made of one or more materials that are different from the one or more materials forming the posterior end portion. In still another and/or alternative embodiment of the invention, the body portion has a cross-sectional shape and size which is substantially the same as the cross-sectional shape and size of one or more regions of the posterior end portion. In yet another and/or alternative embodiment of the invention, at least a section of the body portion has a cross-sectional size and/or shape that is different from one or more regions of the posterior end portion. In still yet another and/or alternative embodiment of the invention, the body portion includes one or more substantially straight or linear regions. In one aspect of this embodiment, at least a majority of the body portion is substantially straight or linear. As can be appreciated, the body portion can have other shapes and/or sizes depending on the desired end use of the insertion tool and/or the end use of the body portion of the insertion tool. In a further and/or alternative embodiment of the invention, the body portion is about 2-10 inches in length; however, other lengths can be used.
In another and/or alternative aspect of the present invention, the insertion tool includes a lower or base portion that is at least partially designed to facilitate in gripping the insertion tool during use. In one embodiment, the base portion includes one or more arcuate portions. In one aspect of this embodiment of the invention, the arcuate portions create an S-shaped look to the insertion tool. In another and/or alternative aspect of the embodiment, the arcuate sections of the base portion create a C-shaped look to the insertion tool. In still another and/or alternative aspect of this embodiment, the base portion is formed by a single arcuate section. In one specific configuration of this aspect, the radius of curvature of the single arcuate section is substantially constant. In another and/or alternative specific configuration of this aspect, the radius of curvature varies at least along one section of the arcuate section of the base portion. In still yet another and/or alternative aspect of this embodiment, the base portion is formed by a plurality of arcuate sections and at least one non-arcuate section. In one specific configuration of this aspect, the radius of curvature of the plurality of arcuate sections is substantially the same. In another and/or alternative specific configuration of this aspect, at least one of the arcuate sections has a different radius of curvature than another of the arcuate sections. In still another and/or alternative specific configuration of this aspect, at least one of the non-arcuate sections of the base portion is substantially straight or linear. In still yet another embodiment of the invention, the cross-sectional shape and/or size of the base portion is substantially constant. In a further and/or alternative aspect of this embodiment, at least one section of the base portion has a different cross-sectional shape and/or area than at least one other section of the base portion. In still a further and/or alternative embodiment of the invention, the base portion is made of a material which is substantially the same as the body portion of the insertion tool. In yet a further and/or alternative embodiment of the invention, at least a section of the base portion includes a material which is different from at least a section of the body portion of the insertion tool. In yet another and/or alternative embodiment of this invention, the curvature of the base portion lies in substantially the same plane as the curvature of the posterior end portion of the insertion tool. In a further and/or alternative embodiment of the present invention, at least a portion of the curvature of the base portion lies in a plane which is different from the plane in which at least a portion of the posterior end portion lies. In still a further embodiment of the present invention, the base section is substantially linear or straight. In yet a further and/or alternative embodiment of this invention, the base portion includes at least one gripping element. In one aspect of this embodiment, the gripping element includes, but are not limited to, ribs, grooves, slots, openings, ridges, pits, corrugations, etc. The gripping element is designed to facilitate in maintaining a grip by the surgeon on the base portion when using the insertion tool. In another and/or alternative aspect of this embodiment, the gripping element includes one or more coatings of a material (e.g. plastic, polymers, etc.) to facilitate in handling the insertion tool during use.
In still another and/or alternative aspect of the present invention, the insertion tool includes one or more smooth surfaces designed to reduce or eliminate damage to surrounding tissue when the insertion tool is inserted, positioned and/or removed from an intervertebral disc space during a surgical procedure. In one embodiment of the invention, the posterior end portion includes one or more smooth surfaces. In one aspect of this embodiment, the outer surface of the posterior end portion is substantially smooth. In another and/or alternative aspect of this embodiment, the inner surface of the posterior end portion is substantially smooth. In still another and/or alternative aspect of this embodiment, the end of the posterior end portion is substantially smooth. In another embodiment of this invention, one or more sections of the body portion of the insertion tool are substantially smooth. In still yet another and/or alternative embodiment of the present invention, one or more sections of the base portion are substantially smooth. In a further and/or alternative embodiment of the present invention, one or more sections of the insertion tool are smoothed by various mechanical means such as, but not limited to, sanding, grinding, polishing, and/or the like. In still a further and/or alternative embodiment of the present invention, one or more surfaces of the insertion tool are smoothed by coating such surfaces to form a substantially smooth surface. Such materials can include, but are not limited to, various types of plastics, polymers, metal plating and the like.
In yet another and/or alternative aspect of the present invention, the insertion tool is made of a biocompatible and/or durable material. The material selected for the insertion tool should be biocompatible, so as not to cause irritation, infection, or other complications during a surgical procedure. The material used for the insertion tool should also be durable enough so that the insertion tool can successfully accomplish at least one of the surgical procedures for which the insertion tool is design. In one embodiment of the invention, the insertion tool includes stainless steel, titanium, chromemolybdenum, cobalt chromium alloy, chrome or chrome alloys, cobalt or cobalt alloys, ceramic (i.e. xirconium oxide ceramic, aluminum oxide ceramic, etc.), and/or polymers (i.e. polycarbonate, polypropylene, polyethylene, polymethylmethacrylate, polysolfone, polymers filled with glass and/or carbon fibers, various types of carbons and/or fiber reinforced polymers, plastic, etc.). In still another and/or alternative embodiment of the invention, the material used to at least partially form the insertion tool is substantially a rigid material; thus, the insertion tool resists any type of deformation during use. In still yet another and/or alternative embodiment of the invention, at least a portion of the insertion tool includes a flexible or semi-flexible material which provides some flexibility to the insertion tool during use. In a further and/or alternative embodiment of the invention, the insertion tool is formed of a material which can be sterilized at least once prior to use. In one aspect of this embodiment, the insertion tool is formed of a material which can be sterilized multiple times for multiple uses.
In yet another and/or alternative aspect of the present invention, the base portion of the insertion tool is configured so as to maintain and/or position one or more spinal implants in an intervertebral disc space. In such a configuration, the posterior end portion and/or the base portion can be used to partially or fully insert a prosthetic implant in the intervertebral disc space. When the base portion is configured for such use, typically, the size and/or shape of the base portion is different from the size and/or shape of the posterior end portion. The total angle of curvature of the base portion can be the same and/or different than the total angle of curvature of the posterior end portion.
In a further and/or alternative aspect of the present invention, multiple insertion tools are used by the surgeon wherein the posterior end portion of one or more of the multiple insertion tools is different from one or more of the posterior end portions of one or more other insertion tools. The use of a set of differently configured insertion tools allows a surgeon to select the appropriate insertion tool that can be best used on a particular patient. Due to the age, height, and/or build of a patient, the intervertebral disc space of a particular patient will differ from patient to patient, thus different sized and/or shaped insertion tools can be used to accommodate the specific physiology of a particular patient.
In still a further and/or alternative embodiment of the present invention, at least a portion of the insertion tool is coated with a material which facilitates in the success of the surgical procedure involving the use of a prosthetic implant. In one embodiment of this invention, the substance includes a material that facilitates in the formation of a graft between one or more vertebrae. In one aspect of this embodiment, the substance includes, but is not limited to, medicine, human tissue, animal tissue, synthetic tissue, human cells, animal cells, synthetic cells, and the like. In another and/or alternative embodiment of the invention, at least one of the substances includes, but is not limited to, a compound that promotes bone or other tissue growth which inhibits rejection of the prosthetic implants, reduces infection, reduces inflammation, reduces pain, promotes healing of surrounding tissue, functions as a locator and/or visual indicator, and the like. In still another and/or alternative embodiment of the invention, the coating material is designed to at least partially control or regulate the release of one or more substances coated on and/or contained within the insertion tool.
In yet a further and/or alternative embodiment of the present invention, the insertion tool includes one or more guide arrangements designed to at least partially guide one or more prosthetic implants, and/or one or more other materials and/or devices into the interior region of the posterior end portion. In one embodiment of the invention, the guide arrangement includes at least one slot and/or groove positioned on at least a portion of the interior surface of the posterior end portion. When such a slot or groove is used, the prosthetic implant and/or other device includes a corresponding structure that is designed to engage the groove and/or slot so as to be at least partially guided by the groove or slot. As can be appreciated, other types of guide arrangements can be used, such as ridges, ribs, and the like. In another and/or alternative embodiment of the invention, the guide mechanism includes one or more movable carriages to which one or more implants can be connected to and/or released therefrom. In one aspect of this embodiment, an implant is connected to a movable carriage and the movable carriage moves the implant at least partially along and/or within the interior region of the posterior end portion. The guide arrangement can include a releaseable connection to release the implant once the implant is properly positioned. In still another and/or alternative embodiment of the present invention, at least one guide arrangement travels substantially along the full interior surface length of the posterior end portion. In another and/or alternative embodiment of the present invention, the guide arrangement is positioned along a portion of the interior surface of the posterior end portion. In still yet another and/or alternative embodiment of the present invention, one or more guide arrangements are positioned on the outer surface of the posterior end portion.
In still yet a further and/or alternative aspect of the present invention, the insertion tool includes one or more side passageways which provide access to the interior region of the posterior end portion during a surgical procedure. The side passageway can be designed to allow materials to be inserted into and/or removed from the interior region of the posterior end portion. Alternatively and/or additionally, the side passageway can allow one or more devices (i.e. lights, cameras, medical devices, etc.) to be at least partially inserted into the interior region of the posterior end portion. Furthermore, the side passageway can be used to facilitate in guiding and/or positioning one or more implants in an intervertebral disc space. In one embodiment of the invention, one or more side passageways are positioned on at least one section of the posterior end portion. In another and/or alternative embodiment of the invention, one or more side passageways are positioned at least partially in the body portion of the insertion tool. In still another and/or alternative embodiment of the invention, one or more side passageways can have a uniform cross-sectional shape and/or size or a variable cross-sectional shape and/or size. In one aspect of this embodiment, the cross-sectional shape and/or size of at least one side passageway is substantially uniform. In another and/or alternative aspect of this embodiment, the cross-sectional shape and/or size of at least one side passageway is variable along the length of the side opening. In yet another and/or alternative embodiment of the invention, the side passageway and/or regions about the two ends of the side passageway can include one or more structures to facilitate in the positioning and/or removal of one or more devices in the side passageway, and prevent and/or allow materials to flow through and/or move into and/or out of the side passageway (e.g. valves, doors, latches, ribs, teeth, etc.). In still yet another and/or alternative embodiment of the invention, one or more side passageways includes a substantially linear passage. In a further and/or alternative embodiment of the invention, one or more side passageways include a non-linear passage. In still a further and/or alternative embodiment of the invention, the pathway of one or more side passageways is positioned substantially perpendicular to the longitudinal axis of the section of the insertion tool that includes the side passageway. In yet a further and/or alternative embodiment of the present invention, at least a portion of the pathway of one or more side passageways is not perpendicular to the longitudinal axis of the section of the insertion tool that includes the side passageway. In one aspect of this embodiment, the angle of deviation from the longitudinal axis is typically about 5-80xc2x0, more typically about 15-70xc2x0, and even more typically about 30-60xc2x0; however, other angles of deviation can be used. In still a further and/or alternative embodiment of the present invention, one end of at least one side passageway is included in the same section of the insertion tool as the other end of the same side passageway. In one aspect of this embodiment, both ends of at least one side passageway are positioned in the posterior end portion of the insertion tool. In another and/or alternative aspect of the embodiment, both ends of at least one side passageway are positioned in the body portion of the insertion tool. In still another and/or alternative aspect of this embodiment, both ends of at least one passageway are positioned in the base portion of the insertion tool. In still yet a further and/or alternative embodiment of the present invention, one end of at least one side passageway is positioned in a different section of the insertion tool of the other end of the same side passageway. In one aspect of this embodiment, one end of a side passageway is positioned in the body portion and the other end is position in the posterior end portion. In another and/or alternative aspect of this embodiment, one end of the side passageway is positioned in the body portion and the other end is positioned in the base portion. In another and/or alternative embodiment of the invention, at least one end of at least one side passageway is positioned on the inner surface of the posterior end portion, body portion, and/or base portion to facilitate in providing access to the inner region of the posterior end portion or base portion.
In another and/or alternative aspect of the present invention, the insertion tool includes one or more markings or other types of visual indicators and/or electronic indicators (e.g. markings, radiolucent material, electromagnetic transmitter, etc.) to facilitate in positioning the insertion tool in the intervertebral disc space. In one embodiment of the present invention, an insertion tool includes one or more visual markings which allows a surgeon to determine the particular position of the insertion tool in an intervertebral disc space.
In still another and/or alternative aspect of the present invention, the insertion tool includes one or more internal passageways that at least partially travel the length of the body portion and at least partially provide access to the inner region of the posterior end portion. The internal passageway can be designed, sized and/or arranged so as to achieve similar goals as the side passageway, as discussed above. The shape and/or size of the internal passageway can be selected to achieve the particular goal of the internal passageway, which are typically similar to one of the goals discussed with respect to the side passageway. In one embodiment of this invention, the inner passageway travels at least a portion of the length of the body portion and at least a portion of the length of the posterior end portion and/or base portion. In another and/or alternative embodiment of this invention, one or more openings of at least one internal passageway are positioned on the inner surface of the posterior end portion, body portion, and/or base portion to facilitate in providing access to the inner region of the posterior end portion, and/or base portion. In still yet another and/or alternative aspect of the present invention, the insertion tool can be used to clean and/or remove material from the intervertebral disc space prior to, during, and/or after an implant is inserted into the intervertebral disc space. In another and/or alternative embodiment of the present invention, one or more sections of the insertion tool can be disconnected. In one embodiment of the invention, the posterior end portion is releasably connected to the base portion. As such, various shaped and/or sized posterior end portions can be selected and connected to the body portion to perform a particular procedure on a particular patient. In another and/or alternative embodiment of the invention, the base portion is releasably connected to the body portion. As such, various shaped and/or sized base portions can be selected and connected to the body portion to perform a particular procedure on a particular patient. In still another and/or alternative embodiment of the invention, one or more regions of the posterior end portion, body portion and/or base portion are releasably connected together. In this embodiment, one or more sections of the insertion tool can be customized for a particular procedure on a particular patient. For instance, the posterior end portion can be customized to have a particular total angle of curvature and/or a particular shape. In another and/or alternative example, the length of the body portion can be extended or shortened. In still another and/or alternative example, the posterior end portion, body portion and/or base portion can be designed to have certain positioned and/or types of side passageways, internal passageways, guide mechanisms, surface profiles, and/or gripping members. In yet another and/or alternative example, the base portion can be customized to have a particular shape and/or size, a particular total angle of curvature, and/or particular gripping elements. In still yet another and/or alternative embodiment of the invention, the connection arrangement can take on many forms such as, but not limited to, threaded connections, tongue and groove connections, twist and/or snap lock connections, clamp connections, and/or the like.
In one specific non-limiting aspect of the present invention, there is provided an insertion tool and method of using an insertion tool to assist in and/or facilitate in the insertion of a medical device (e.g. prosthetic implant) into the intervertebral disc space created after all or a portion of a spinal disc is removed. The insertion tool can include a straight body section with an arcuate posterior end portion and/or arcuate base portion, and which can be hand held and/or guided mechanically or by some other method. The insertion tool can be designed to be at least partially inserted by a surgeon, into a space in a spinal column, which space has been created by the removal of all or a portion of a spinal disc, either by the surgeon or due to disease or birth defect. The insertion tool is designed to facilitate in the insertion of a prosthetic implant, to serve as a guide for such prosthetic implant, to serve as a protective barrier to ensure that the prosthetic implant being inserted does not stray beyond its intended target location, and/or to serve as a protective barrier to ensure that the prosthetic implant does not damage adjacent tissue. The prosthetic implant can be designed to facilitate in the turning and/or maneuvering and/or positioning of the prosthetic implant in an intervertebral disc space. The insertion tool can have a posterior end which is designed to have various size widths, heights, and/or thicknesses so that the surgeon can select the size insertion tool for a particular patient""s needs. The insertion tool can be made of ceramic, metal, plastic, and/or bone materials which can be reusable, after sterilization, and/or disposable. The insertion tool can be a solid material with no openings or slots. The insertion tool can include one or more channels on the exterior and/or interior surface of the insertion tool, so as to permit one or more prosthetic implants or other devices to be inserted into a channel to assist in the positioning of a prosthetic implant relative to the insertion tool and/or in a proper position in the intervertebral disc space. The insertion tool can include one or more passageways which can be used to insert a light, fiber optic cable, camera, laser, and/or used as or with an irrigation system and/or suction system. Alternatively or additionally, the one or more passageways can be used to permit the introduction of medication, bone marrow, autologous growth factor, and/or other efficacious material into the inner region of the posterior end portion and/or base portion. Further and/or alternatively, the passageways can be used to insert cements, adhesives, and/or other materials which facilitate in the securing of the prosthetic implant in position in the intervertebral disc space. The insertion tool can have grooves on the exterior surface of the posterior end portion, body portion, and/or base portion which can be designed to have uses similar to the grooves as discussed above that can be positioned on the interior surface of the posterior end portion and/or base portion. The insertion tool can have a posterior end portion and/or a base portion and/or a body portion which has a substantially constant cross-sectional shape and size, and/or can have a varying cross-sectional shape and/or size. The insertion tool can be designed such that the thickness of at least a portion of the posterior end portion and/or base portion can be increased in thickness and/or reduced in thickness during a surgical procedure. The ability to increase the thickness of at least a portion of the posterior end portion and/or base portion can be used to facilitate in maintaining the spacing between two adjacent vertebrae. The reduction in thickness of at least a portion of the posterior end portion and/or base portion can be used to facilitate in inserting and/or removing the insertion tool from the intervertebral disc space. The insertion tool can be rigid, semi-rigid, or flexible depending on the desired end use of the insertion tool. The insertion tool can be used for various types of surgical procedures involving intervertebral disc spaces or other mammalian surgical procedures. The insertion tool would be particularly useful for kyphoplasty, vertebroplasty, and/or the insertion of spinal fusion cages and/or artificial discs into an intervertebral disc space. The insertion tool can have a smooth exterior surface or an unsmooth exterior surface depending on the intended end use. The insertion tool may have one or more markings to indicate measurements and/or positioning indicia on the exterior surface of the insertion tool, which markings can utilize a simple numbering or coloring systems and/or some other appropriate measuring methodology to facilitate in the positioning the insertion tool in the intervertebral disc space.
It is a principle object of the present invention to provide an insertion tool that can be used to position and/or insert one or more prosthetic implants between two vertebrae.
It is another and/or alternative object of the present invention to provide an insertion tool which minimizes or prevents damage to surrounding tissue during the use of the insertion tool.
It is yet another and/or alternative object of the present invention to provide an insertion tool which can easily and efficiently position one or more prosthetic implants between two adjacently positioned vertebrae.
It is yet another and/or alternative object of the present invention to provide an insertion tool which reduces the failure rate of prosthetic implants during a surgical procedure.
It is yet another and/or alternative object of the present invention to provide an insertion tool that is at least partially made of a biologically compatible material.
It is still another and/or alternative object of the present invention to provide an insertion tool that includes markings to enhance the visibility of the insertion tool and/or provide location and/or positioning information for the insertion tool.
It is yet another and/or alternative object of the present invention to provide an insertion tool which facilitates in the insertion of a prosthetic implant, serves as a guide for such prosthetic, serves as a protective barrier to ensure that the prosthetic implant does not stray beyond its intended location, and/or serves as a protective barrier to help ensure that the prosthetic implant does not damage adjacent tissue.
It is yet another and/or alternative object of the present invention to provide an insertion tool which includes a posterior end portion that approximates the interior curve of the intervertebral disc space into which the prosthetic implant is inserted.
It is yet another and/or alternative object of the present invention to provide an insertion tool that includes one or more gripping elements to facilitate in the positioning of the insertion tool in the intervertebral disc space.
It is still another and/or alternative object of the present invention to provide an insertion tool which includes one or more guiding arrangement used to at least partially guide and/or position one or more prosthetic implants or materials and/or devices in an intervertebral disc space.
It is still another and/or alternative object of the present invention to provide an insertion tool which includes one or more side passageways to provide access to the interior region of the posterior end portion and/or base portion from the side of the insertion tool.
It is still another and/or alternative object of the present invention to provide an insertion tool that includes one or more internal passageways which provide access to the interior region of the posterior end portion and/or base portion.